Reflecting-galvanometer.



-N0.73o,o61. y Y APAZIENTE) JUNE`2,1903. E. WESTON.

REFLBGTING GALVANOMBTBR.

APPLICATION FILED JULY 9, 1902. N0 MODEL. V 2 SHEETS-SHEET 2.

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NITED STATES' Patented June 2,1903.

PATENT p OFFICE.

EDWARD WESTON,OF NEWARK, NEW JERSEY.`

lEFl ECTlNG-GALVANOMETER.

SEDECIFCATION' forming part of Letters Patent No. 730,061, dated June 2, 1903.

Application fura my 9,1902, serai 110.114.941. (remodel.)

To @ZZ whom it nfl/ty concern:

Be it known that I, EDWARD WESTON, a subject of the King ofGreat Britain, residing at Newark, in the county of Essex and State 5 of New Jersey,rhave madea new and useful Invention in Retlecting-Galvanometers, of which the followingis a specification.

My invention is directed particularly toV improvements in reflecting-galvanometers in the field-magnet of the instrument in 'con-4 nection with the casing or cover, the same being so devised that said'mag'net may be readily detachable and will always bear a fixed or definite relation to the movable coil which controls the movement. of the mirror;`

third, to provide novel means vfor effecting the circuit connections between the terminals and the coil, the same being so arranged that when the coil, its core, and the coil and core.

supports, together with the mirror, constituting what I term the movement, are removed as a unit from the instrument the circuit is interrupted between the ixed terminals carried-bythe movement and yieldingterminals carried by the casing or cover;

magnet clamp, the binding-posts, the spirit- 1evel the tilar suspension, the mirror, and two of the leveling-screws being shown in side elevational view. Fig. 2 is a side elevational view of the movement detached from the instrument and as seen looking at this `tire interior structure.

fourth, to provide novel means for lifting and secur ng the coil againstrotary movement and r all of which like letters and numerals ot re part as shown in position in Fig. 1 from right to left. Fig. 3 is aV transverse sectional View taken through Fig.'l on the line Y Y, a part of the cover being broken away, so as to show the interior structure. Fig. 4: is a plan View as seen looking at Fig. l from the bottom toward the top of the drawing, the casing of the instrument, however, being removed in this view for the purpose of showing the en- Fig. 5 is a detail View illustrating the means for supporting the coil and the mirror.

In the construction of delicate electrical measuring instruments, such as reliectinggalvanometers, where the movable coil, its ilar suspension, and the mirror carried thereby are removable asa unit from the body of theinstrument it is important that the coil and the magnetizablel core which it surrounds shall bear a definite or fixed relation to thepoles of the field-magnet when the movement is in place and thatjthe coil should move when the instrument is leveled and adjusted freely in the air-space between the poles ot' the field-magnet and the magnetizable core. It is also important that the field-magnet itself be so secured to the casing of the instrument as to bear always a constant relation thereto, so that when it is once secured in place within the casing lthe movement may be removed at any time and restored, with the assurance that the instrument Will performY its functions with certainty and accuracy.

With instruments of this type owing to Vthe delicacy of the movable parts it is always `necessary to lift the movable coil and the mirror, so that their weight shall be taken off the delicate lar suspension and that the coil shall be so locked or held that it will not have a tendency to move from its normal position about the core. It is also important that the electrical connections between the coil and the binding-posts of the instrument v shall beas simply and compactly arranged as possible, so that accurate results shall always be obtained. It was with these especial objects in view that the improvements embodied in the present invention were conceived and reduced to practice by me.

Referring now to the drawings in detail, in

Ioo i erence represent like parts wherever used, c represents the casingof the instru1nent,made, preferably, ot' some non-magnetic metal, as brass, and of the conformation shown, said casing being providedwith three or more detachable legs Z, slitted at their outer ends for the purpose of receiving the usual levelingscrews.

a represents the lid or cover thereof, which is secured and accurately fitted to the upper edge of the casing by a number of screws. This cover is made also of non magnetic metal and is provided at its axial center with a downward extension, in which is drilled a hole adapted to receive a screw s for the purpose ot securing the field-magnet in place.

m represents the permanent field-magnet, made, preferably, of cylindrical form, as shown in Figs. 3 and 4, and having drilled in its upper surface three holes or openings, in which are secured soft-metal plugs e, preferably of iron, said plugs being, in eect, integral with the magnet and having drilledin their upper ends cone-shaped holes for the purpose of receiving the coned ends of three metal pins 23, secured directly to the under surface of the casing.

t represents a metallic clamp ot' tripod nature, the outer ends of the legs of which are accurately planed off, so as to rest when in position against the lowersurface of the fieldmagnet m, said clamp being provided at its center with an opening, through which the screws is adapted to pass. The length of the cone-shaped pins p is such and they are so secured to the under surface of the lid or cover a that when the magnet is held in place bythe screws and clamp t in the manner shown its opposite faces will be in planes parallel with the trued face of the lidY or cover secured to the upper edge of the casing for the purpose of assuring mathematical accuracy between the coil of the movement and the magnetic field through which it moves.

8 is a spirit-level ot' well-known form, and b b are binding-posts, all secured in the upper surface of the lid or cover. In one side ot' the lid or cover is constructed an accurately-turned opening having a definite relation to the poles of the field-magnet m, the inner cylindrical surface of said opening being turned in a lathe, so as to be practically concentric with the curved portions of the field-magnet poles. (See Figs. 3 and et.)

g is a mirror-cham ber having substantially the conformation shown in Fig. 2 and having cast integral therewith a downwardly-cylindrical portion provided with a flange, as shown,and astil l further downwardly-extending portion h, the lower end of which extends su bslantially at right angles to the body portion, so as to act as a support for the lower pivotal part of the movable coil q. To the upper end of the mirror-chamber is secured byinsulating-joints the usual double adjusting suspension-tubes 1.1, made of metal and provided at their upper ends with a rod to which is secured the filar suspension f.

y is an adjusting-screw for regulating the movement of the rod, and hence the vertical adjustment of the coil q.

q is the movable coil, which is constructed substantially like the similar part disclosed in United States Patent No. 611,722, granted to me on the 4th day offl October, 1808, the pivot-plates G in the present instance, however, being attached thc lower one directly to a spiral spring r, expansible in the direction of its length, withits lowerend connected directly to a conducting-pin u, located in the axial center of a hard-rubber or otherinsulating-sleeve t', detachably secured by a screwj in the slitted end ot' the core-support 7L, and the upper one to a rigid metallic standard o, the upper end oli' which is connected directly to the lower end of the filar suspension f. This rigid metallic standard o also acts as a support for the mirror n, which is located directly in the rear of an opening in the mirror-chamber, provided with a glass or other transparent medium, as is usual in such instruments.

7c represents the maguetizable core, which is located with its axis in the axial line of the magnetic iield between the curved polepieces of the permanent magnet m. This core is secured directly to the core-support 7L by dowel-pins and one or more screws, as shown.

w represents an insulated conductor secured at its upper end to the inner 0f the tubes fu and extending thence directly to a contacting pin 1, constituting a lixed terminal, secured to and insulated from the under surface of the cylindrical portion ol the mirror-chamber and adapted to rest when in position with its free end upon one of the springs or yielding terminals 7, (see Fig. 4,) connected to one of the binding-posts Z1, insulated from the lid or cover of the instrument. The other binding-post b is similarly insulated and is provided with a similar spring or yielding terminal 7, the free end of which is adapted to rest against another conducting-pin 2, constituting a second fixed terminal, carried by and insulated from the mirror-chamber, said conductingpin being connected by a continuance of the conductor w to the pin u, which in turn is connected directly to the coil q through the lower pivotplate 6, the upper pivot-plate 6, connected also to the coil, being connected directly through the standard o, iilar suspension f, and rod :t to the tube c.

Near the lower end of the downwardly-extending portion h, which constitutes the coresupport, is a lug or extension 9, provided with a hole or opening adapted to receive au upwardly extending rod c, which passes through a similar opening in the base of the mirror-chamber and is provided with a laterally-extending arm 3, adjustably secured to IOO l it, with its outer end bent back upon itself parts, so that the filar suspensionfis 'relieved' of their weight.

4 is a spiral spring which surrounds the rod z, with its lower end resting against the lug or extension 9 and its upper end against a pin 10, carried by the rod.

5 is an operating cam or eccentric pivotally supported by the mirror-chamber, with its operating end resting against the upper end of the rod z.

In the construction of this instrument, as before indicated, the opening in the lid or cover ct, which receives the movement, is turned in a lathe with mathematical nicety, and the permanent field-magnetv m, is sup- 'vported by the tripod clamp t, screw s, softmetal plugs e, and cone-shaped pinsp in such manner that the axial line of the magnetic field of the curvilinear pole pieces passes through the mathematical center of the cylindrical opening in the lid. In like manner the magnetizable core 7s is turned with such exactness and so supported by the dowel-pins and screw that its axis coincides with the before-mentioned axes and that the air-spaces be- 'tween its curvilinear surfaces and the curved poles of the held-magnet are symmetrical in every particular. drical portion of the mirror-chamber and the face-fiange thereof, together with lthe upper surface of the lid at this point, are 'so turned in a lathe that when all of the parts are secured finally in positionthe axial lines of thev magnetic field of the magnetizable core k, the coil q, and the filar suspension j' are in absolute coincidence when the instrument is properly leveled and adj usted. This feature of mathematical adjustment constitutes anv important elementin myinvention, the structural arrangement being such that the movement, embracing the parts shown in Fig. 2, may be withdrawn from the instrument at any time for adjustment or repairs and again restored with the absolute assurance that all of the parts of theinstrument will preserve their original relation to each other.

As shown in Figs. 1 and 2, the instrument is ready for use with the coil q in its lower position and the cam or eccentric 5 in a vertical position, thus forcing the rod a' to its lower position against the stress ofthe spring 4. When it is desiredto move the instrument or disturb it in anyway, it is only necessary to rotate the cam or eccentric 5 from left to right in the direction of the arrow, (see Fig. 2,)

when the spring 4 will cause the rod a' and arm 3 to be lifted, and hence to lift also the coil q, standard o, and mirror at, so that the lower end of the coil will come into mechanical contact with' the lower end of the magnetizable core 7c and be 'locked or maintained In like manner the cylin` against movement or rotation, and the weight of these parts will, for like reason, be removed from the delicate Iilar suspension f.

Although the present invention is directed especially to improvements in reecting-galvanometers, I do not limit all of the features thereof to use in connection with such inst-ru-l ments,`as obviously a number of the features embodied in this invention may have a general use in connection with electrical measuring instruments or in connection with other instruments of precision where it is desirable to have a mathematical relation of parts when assembled for operation, and my claims are genericastoallsuch usesoradaptabilities. To make a single illustration, the manner of'sustaining or supporting the permanent fieldmagnet m in connection with the lid or cover of the instrument through the agency of-a clamp may be applied With equal practicability to the case o f the instrument directly and for use in connection with electricalmeasuring instruments generally; nor do I limit this feature of the invention to the use of a single clamp if when combined with the means of support with the lid or the case in the nature of soft-metal plugs and cone shaped steady or centering pins p, as my claims are designed to be of such scope as to include all such obvious uses and modified forms. I Wish it also understood that by the term movement used throughout the specification and in the claims hereinafterI mean the movable part of an 'electrical measuring instrument and the adjunct parts connected thereto and adapted to be removed therewith from the body of the instrument as a unit, the same constituting either a coil and the indicating parts adapted to be moved thereby or any magnetizable movable agent, as anY 'of affording a means of support therefor, as

this feature constitutes in part the subjectmatter of another application filed by me in the United States Patent Office on the 7th day IIO of May, 1902, and bearing Serial No. 106,242.

masses embedded in itsvface, .togetherwivth steady or centering pins or means securedl to the lid or casing and one or more clamps` for' securing the magnet firmly in position..k

Having thus described my invention, what I claim, and desire to secureby Letters Patent of the United States, is-

1. A reflecting galvanometer having its ield-magnetsecured directlyto the lid or cover of the instrument and in a fixed or definite relation thereto; in combination With a detachable movement consisting of a suspended mirror and coil and a magnetizable core and supports therefor, so secured in the lid or cover that the axes of the magnetizable core, the movable coil and the support for the latter are coincident when the instrument is leveled, substantially as described.

2. A relecting-galvanometer having its field-magnet detachably secured to the lid or cover; in combination with a movement having a magnetizable core,a movable coil and a mirror; together with a mirror-chamber and supports for the coil, the mirror and the magnetizable core operatively connected to the mirror-cha mber, the latterbeing provided with a downwardly-extending cylindrical portion adapted to fit in an opening in the lid or cover and a flange adapted to rest upon the upper surface thereof, said parts being relatively so constructed that the axial lines of the magnetic field, the magnetizable core, the coil and its support are coincident When the instrument is leveled, substantially as described.

B. A reiecting-galvanometer provided with a field-magnet and a movement both secured to the lid or cover of the instrument; together with binding-posts operatively connected to yielding terminals; in combination with fixed terminals carried by the Inovement and electrically connected With the coil thereof, said xed terminals being adapted to make good electrical contact with the yielding terminals, when the movement is secured in place, substantially as described.

l. An electrical measuring instrument provided with afield-magnet and means for maintaining it in a definite relation to the lid or cover; in combination with a clamp having a series of legs and adapted to firmly secure the magnet against the before-mentioned means, substantially as described. I

5. An electrical measuringinstrument provided With a iield-magnet having soft masses embedded in one of its faces; in combination with a lid or cover for the instrument provided With steady or centering pins adapted to rest in centering-holes in the before-mentioned masses; together with a clamp or clutch adapted to secure the magnet to the lid or cover and in a definite relation thereto, substantially as described.

6. An electrical measuring instrument pro vided With a casing and a lid or cover therefor; in combination with a field-magnet secured directly to the under surface of the lid or cover bya clamp; together with a movement embracing a magnetizable core, a coil and supports therefor, the relative construction of the several parts being such that when the movement is in position the axes of the magnetic field, the core and the coil are substantially coincident, substantially as described.

7. Means for lifting the coil and mirror of a reflecting-galvanometer into their upper positions, consisting of a rod having an arm extending laterally beneath the upper end of the coil and a spring adapted normally to hold the rod in its upper position; together with means for locking the rod in its lower position, substantially as described 8. Areflecting-galvanometer provided with a movable coil and mirror secured thereto; in combination with means for lifting the coil and the mirror off their support and locking them against movement, said means consisting of a vertically-moving rod provided With an arm extending laterally beneath the upper end of the coil and a spring tending normally to lift the rod into its upper position; together With an eccentric or cam adapted to force the rod into its lower or inoperative position, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

EDWARD WESTON.

Witnesses:

WILLIAM I-I. YAWGER, ADELBERT P. BENno'rHE. 

